The present invention generally relates to electrical slide switches and more particularly to a detented slide mechanism for an electrical slide switch.
Electrical slide switches have long been used to control the operation of many devices in our everyday experience, including volume and other controls for audio and video equipment, dimmers for lights among a multitude of other products. Such slide switches have also been used for controlling the operating speed of many kinds of variable speed hand tools. One such speed control slide switch is provided in electrical powered hand tools that are used in woodworking and the like as marketed by the S-B Power Tool Company of Chicago, Ill. under the Dremel trademark. Such tools have an elongated generally cylindrical configuration with a rotating output shaft at one end to which various tools can be attached for performing tasks such as engraving, carving, polishing, cleaning, cutting, grinding, sharpening and sanding. Many of these tools have a variable speed capability which is controlled by operation of a slide switch that is located near the cord end of the tool and which is movable in a circumferential direction between an off position and a maximum speed position. The slide switch has a switch lever that generally follows the curvature of the cylindrical configuration of the housing. The switch mechanism used in the prior art Dremel tool has a smooth operating action in that it can be moved by a user relatively easily without significant resistance. While it has sufficient resistance that the switch normally does not move as a result of vibration of the tool during normal use, excessive vibration or unintended contact by the user can change the position of the switch on occasion.
The provision of a detenting mechanism in slide switches is of course generally known in the art and it also known that the manner in which such detenting action is implemented can significantly add to the complexity of the design of a slide switch.
The present invention is an improved switch mechanism for a slide switch of the type that provides a variable output resistance value as a function of the position of the switch, wherein a switch lever can be moved from a first position to a second position and to vary the resistance value of the switch, with the switch having a detented or clicking action during movement. Such detenting action enables the switch to more reliable remain at a location that is selected by the user, and also enables the user to more reliably return the switch to a desired setting. The switch mechanism embodying the present invention provides such detenting action using a mechanism that has a switch lever that travels in a curved or arcuate path when moved by a user and still provide a uniform resistance to movement detenting action through the entire range of movement of the switch lever.